Aim. This study was designed to perform the comparative evaluation of functioning of antioxidant system of blood in patients 137 Kubanskij nauchnyj medicinskij vestnik 2018; 25 (5) suffering from psychostimulants and opioids addiction syndrome.Materials and methods. The study was performed using biological material of 52 patients divided into 3 groups. Patients who were considered to be conditionally healthy were included in the 1st (control) group. The 2nd group was presented by the patients suffering from opioids addiction syndrome, the 3rd group included patients suffering from psychostimulants addiction syndrome. Some parameters of the thiol metabolism and general antioxidant activity were identified in the blood plasma of patients as well as the level of products of oxidative modifications of biomolecules and the activity of enzymes of antioxidant protection in the erythrocytes.Results. In the course of the performed studies it was revealed that the decreased antioxidant activity of the blood plasma by 28-40% was characteristic for the examined patients as well as the imbalance of enzymes of the antiradical protection of erythrocytes and the high intensity of oxidative modifications of biomolecules characterized by the increase in the thiobarbituric value by 2,4-3 times. The activity of superoxide dismutase in erythrocytes of patients of both test groups decreased by 35-43%, while the catalase activity increased by 15-21% in comparison with the relevant indices of the control group. The presence of such changes in the functioning of enzymes of the antioxidant protection can indirectly prove the presence of hypoxia in the examined patients. Besides, the increase in the content of easily-accessible thiol groups by 2,6-2,8 times and the decrease in the content of SH-groups difficult for access by 2,5-3,2 times was noted in patients suffering from the drug addiction. The reconstruction of the balance of various types of thiol groups can be associated with the confirmatory reconstruction of protein molecules induced by the oxidative modifications and combining of toxins.Conclusion. The study in prooxidant-antioxidant status revealed the common traits in the disease pattern in patients suffering from various types of drug addiction. The received data allow us to discuss the perspectives of the criteria search for the laboratory biochemical monitoring of the patients with drug addiction and the possibilities of the antioxidant correction of metabolic disorders as a component of the complex therapy for such patients.